Ant example source code file (StreamPumper.java)

This example Ant source code file (StreamPumper.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

cannot, exception, exception, illegalstateexception, inputstream, interruptedexception, interruptedexception, io, ioexception, outputstream, outputstream, runnable, streampumper, streampumper

The StreamPumper.java source code

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

package org.apache.tools.ant.taskdefs;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Copies all data from an input stream to an output stream.
 *
 * @since Ant 1.2
 */
public class StreamPumper implements Runnable {

    private InputStream is;
    private OutputStream os;
    private volatile boolean finish;
    private volatile boolean finished;
    private boolean closeWhenExhausted;
    private boolean autoflush = false;
    private Exception exception = null;
    private int bufferSize = 128;
    private boolean started = false;

    /**
     * Create a new stream pumper.
     *
     * @param is input stream to read data from
     * @param os output stream to write data to.
     * @param closeWhenExhausted if true, the output stream will be closed when
     *        the input is exhausted.
     */
    public StreamPumper(InputStream is, OutputStream os,
                        boolean closeWhenExhausted) {
        this.is = is;
        this.os = os;
        this.closeWhenExhausted = closeWhenExhausted;
    }

    /**
     * Create a new stream pumper.
     *
     * @param is input stream to read data from
     * @param os output stream to write data to.
     */
    public StreamPumper(InputStream is, OutputStream os) {
        this(is, os, false);
    }

    /**
     * Set whether data should be flushed through to the output stream.
     * @param autoflush if true, push through data; if false, let it be buffered
     * @since Ant 1.6.3
     */
    /*package*/ void setAutoflush(boolean autoflush) {
        this.autoflush = autoflush;
    }

    /**
     * Copies data from the input stream to the output stream.
     *
     * Terminates as soon as the input stream is closed or an error occurs.
     */
    public void run() {
        synchronized (this) {
            started = true;
        }
        finished = false;
        finish = false;

        final byte[] buf = new byte[bufferSize];

        int length;
        try {
            while ((length = is.read(buf)) > 0 && !finish) {
                os.write(buf, 0, length);
                if (autoflush) {
                    os.flush();
                }
            }
            os.flush();
        } catch (Exception e) {
            synchronized (this) {
                exception = e;
            }
        } finally {
            if (closeWhenExhausted) {
                try {
                    os.close();
                } catch (IOException e) {
                    // ignore
                }
            }
            finished = true;
            synchronized (this) {
                notifyAll();
            }
        }
    }

    /**
     * Tells whether the end of the stream has been reached.
     * @return true is the stream has been exhausted.
     */
    public boolean isFinished() {
        return finished;
    }

    /**
     * This method blocks until the stream pumper finishes.
     * @throws InterruptedException if interrupted.
     * @see #isFinished()
     */
    public synchronized void waitFor()
        throws InterruptedException {
        while (!isFinished()) {
            wait();
        }
    }

    /**
     * Set the size in bytes of the read buffer.
     * @param bufferSize the buffer size to use.
     * @throws IllegalStateException if the StreamPumper is already running.
     */
    public synchronized void setBufferSize(int bufferSize) {
        if (started) {
            throw new IllegalStateException(
                "Cannot set buffer size on a running StreamPumper");
        }
        this.bufferSize = bufferSize;
    }

    /**
     * Get the size in bytes of the read buffer.
     * @return the int size of the read buffer.
     */
    public synchronized int getBufferSize() {
        return bufferSize;
    }

    /**
     * Get the exception encountered, if any.
     * @return the Exception encountered.
     */
    public synchronized Exception getException() {
        return exception;
    }

    /**
     * Stop the pumper as soon as possible.
     * Note that it may continue to block on the input stream
     * but it will really stop the thread as soon as it gets EOF
     * or any byte, and it will be marked as finished.
     * @since Ant 1.6.3
     */
    /*package*/ synchronized void stop() {
        finish = true;
        notifyAll();
    }
}